基于Lex和Yacc的开放式并联机床后置处理系统开发

针对常见数控系统的后置处理模块具有专用、封闭等特点,从而限制了其在新型并联加工装备中的应用的问题,研究了开放式并联机床后置处理系统开发的关键环节.首先,基于Lex和Yacc编译工具实现了数控代码的解析功能,此功能能够适用于不同体系的数控代码格式,提高数控系统的开放性和通用性.其次,对并联机床后置处理中的关键算法进行了研...     

CAXA软件在单板机控制器式线切割机床的应用

CAXA线切割软件拥有强大的CAD绘图功能和丰富全面的CAM功能,可以方便地将CAD/CAM技术与单板机控制器式线切割机床进行有效结合。主要介绍基于CAXA的单板机控制器式线切割机床CAD/CAM化解决方案。     

通用后置处理中生成固定循环加工指令

介绍了在通用后置处理系统中输出各种固定循环加工指令的实现方法。通过对当今主流数控机床编程手册进行研究，设计数控机床特性文件，该文件与刀位轨迹文件，刀具信息相结合就可以输出各类数控机床的循环加工代码。采用相同的实现方法。也可以实现其它数迭机床控制指令的输出。该系统已经在FUNAC，FIDIA，SIEMENS等数控机床进行成功的试验。     

进给系统热变形对机床运动重复性误差的影响研究

为了分析进给系统热变形对机床运动重复性误差的影响，提出了一种基于分层模型-移动热源的进给系统热变形建模方法。将进给系统分为丝杠层和工作台层，将移动结合面等效为弹簧。采用实体单元和接触单元建立了有限元模型，在丝杠和导轨上施加移动热源，获得进给系统的温度场和热变形。在此基础上，分析了工作台进给速度、轴承预紧力矩和滑块支撑距离对机床运动重复性误差的影响，并进行了实验验证。研究表明，工作台进给速度和轴承预紧力距对机床运动重复性误差的影响较大，滑块支撑距离对机床运动重复性误差的影响较小。研究结果为在机床设计和装配中减小机床运动重复性误差提供了依据。     

带冷却系统的XK717数控铣床主轴部件热特性分析

机床主轴系统是机床的核心部件，其热特性的好坏，直接影响机床的加工精度；以建立主轴系统的有限元模型，结合主轴系统与普通水箱之间的冷却模型，对带有冷却套的主轴系统进行了热特性分析，得出了主轴系统的热特性曲线；根据分析结果，对XK717数控铣床主轴部件冷却套的布局进行了改进设计，为优化数控铣床主轴系统提供了理论依据。     

浅谈精密机床主传动变速系统的设计

精密机床主传动变速系统是机械制造和加工的关键工程。本文主要探讨了精密机床主传动变速系统的设计问题。主要从主传动系和精密机床进给系进行设计，以期对机械工程提供有益参考。     

气瓶焊接设备的虚拟改装设计

 基于虚拟制造(VM)技术讨论了设备虚拟改装的原理和特点，提出虚拟改装系统的实现方法和运行模式，讨论了老旧机床本体及新附加装置的建模方法，并在工业用非重复充装焊接钢瓶生产线建设中，进行了焊接专机的改装实践.利用虚拟技术确保机床改装一次性成功，降低老旧设备改造的工程成本，在生产中能满足工艺要求.     

机床主轴系统动力学特性研究进展

介绍机床主轴系统动力学特性的研究进展。主轴系统的建模、动态特性的研究方法、轴承参数及加工条件等多种因素对机床主轴动力学特性的影响方面作了系统阐述，简要介绍主轴系统的优化设计方法以及结构改进。对国内和国外的研究进展进行了比较，总结机床主轴系统动态特性研究方面的不足，为今后的研究提供参考。     

基于本体的机床高速主轴数字化集成技术研究

为提高机床高速主轴设计的效率,针对机床制造企业在数字化设计系统的过程中如何集成各种信息资源和知识的问题,以机床高速主轴系统设计开发为研究对象,提出了一种基于本体知识的机床高速主轴协同设计集成系统平台框架.系统采用基于本体论的知识建模方法,利用特征参数度量的相似实例检索方法,以及基于实例推理技术、面向设计流程的知识驱动设...     

Total precision inspection of machine tools with virtual metrology

The technology of virtual metrology (VM) has been applied in the semiconductor industry to convert sampling inspection with metrology delay into real time and online total inspection. The purpose of this study is trying to apply VM for inspecting machining precision of machine tools. However, machining processes will cause severe vibrations that make process data collection, data cleaning, and feature extraction difficult to handle. Thus, the tasks of how to accurately segment essential parts of the raw process data from the original numerical-control file, how to effectively handle raw process/sensor data with low signal-to-noise ratios, and how to properly extract significant features from the segmented and clean raw process data are challenging issues for successfully applying VM to machine tools. These issues are judiciously addressed and successfully resolved in this paper. Testing results of machining standard workpieces and cellphone shells of two three-axis CNC machines show that the proposed approach of applying VM to accomplish total precision inspection of machine tools is promising.     

Real-time cutting simulation system of a milling operation for autonomous and intelligent machine tools

The conceptual architecture of autonomous and intelligent machine tools has been proposed not only to generate flexibly the process and operation plan but also to utilize the machine tools and cutting tools' performance while satisfying the requirements of the products and avoiding unexpected machining trouble. In order to realize the autonomous milling, machining strategy such as tool paths and cutting conditions must be decided, not in advance like current NC machining, but in a real-time manner. The objective of this research is to develop a real time machining optimization with machining simulation. Consequently, a cutting simulation system called a virtual machining simulator has been developed for this purpose. This simulator can calculate the changing geometry of the workpiece and estimate the instantaneous cutting force, torque, etc using the physical model. This estimated information enables the system to decide the suitable cutting conditions according to the machinability evaluated. In this paper, the machining status is evaluated and the cutting conditions are modified in real time so that the requirement of the machining operation is satisfied by referring to the physical model. The reliable and safe machining operation is carried out by maintaining the cutting force and torque desired value.     

自由曲面的CNC直接插补加工技术

在ＣＮＣ系统上直接根据曲面几何定义与加工工艺参数对多轴贡面加工的连续运动轨迹进行实时插补控制，在ＣＮＣ上直接在ＡＰＴ高级语言编程，极大地科化了零件程序，并可在线修改与补偿机床运动结构、刀具形状尺寸及加工作量等工艺参数，使曲在线曲面精加工经济而高效。在单ＣＰＵ硬件环境下实现了从一般二次曲线到复杂的参数组合曲面，从两轴加工到复杂的五轴联动功能，可采用多种加工刀具与加工方式，可实时检测与处理刀具干涉，并     

Optimisation of machining parameters by criterion of maximum productivity

The optimisation of machining parameters for machine tools using the criterion of maximum productivity rate is not a new problem – many unresolved issues remain. The intensification of machining processes leads to changes in the productivity rate; analytically defining optimal machining parameters for the maximum productivity rate in real-world manufacturing processes is, therefore, an important problem that needs to be addressed. This paper aims to formulate a mathematical model for the optimisation of cutting processes on machine tools based on the criterion of maximum productivity rate. The mathematical model is based on technological data, machining and reliability parameters of the machine tool units. Several practical applications are discussed.     

Effective corner machining via a constant feed rate looping tool path

In the finish machining of a pocket corner, varying radial depth of cut is generally encountered by the end milling tool during the entry into and exit from the corner. This leads to substantial variability of the machining process. This paper presents the generation and application of a multiple looping tool path for corner machining with the objective to reduce the machining variability and improve the machining efficiency. Material removal rate is selected as the measure for the machining variability. To reduce the material removal rate for a straightforward corner machining tool path, feed rate needs to be decreased as the end mill approaches the corner apex and increased as it exits the corner. Instantaneous changes of feed rate are not possible in practice due to practical limitations on the servo drive system of common machine tools. A tool path of constant feed rate is thus preferred for effective corner machining. The looping tool path proposed in this work is composed of a series of smoothly connected linear and circular segments to ensure its applicability for all machine tools. For a given corner geometry, a single-cutter as well as a double-cutter strategy have been introduced to maximise the machining efficiency. Various case studies were carried out to examine the resulting material removal rate and total machining time for different machining operations.     

用激光干涉仪检测双丝杠驱动加工中心的方法与评定

介绍了使用激光干涉仪检测双丝杠驱动加工中心时,选择测量轴线的有效位置,能够真实地反映加工中心轴线的运动定位状态;提出检测双丝杠驱动加工中心定位精度和重复定位精度的方法,通过调整激光干涉仪和位移镜组件的安装位置,获得数控机床及加工中心的检测精度,并根据自动采集获得的测量数据进行有效地补偿,以提高和恢复数控机床及加工中心的最佳定位精度.     

Cost of cutting tools and total machining costs as a function of the cutting-tool reliability in automatic flow lines

This paper explains an approach to establishing the total reliability of cutting tools on feeding automatic machine lines as a function of time, and based on this the establishment of cutting-tool costs and total machining costs as a function of cutting-tool reliability.

Based on observations, made over a long period, cutting-tool reliability is established for certain operations (Weibull distribution), and the total reliability for the whole line established as the product of the individual operations.

Cutting-tool costs are shown as the sum of tool replacement, sharpening and depreciation costs, and total machining costs as the sum of machining values, machine tools and cutting tools.

By variation of the cutting-tool replacement time, the tabular change dependencies are obtained as a function of cutting-tool replacement time. By elimination of replacement time from the above dependencies, the cutting-tool cost changes and machining costs are obtained as a function of the cutting-tool reliability. These could prove valuable in the choice of optimal cutting-tool replacement times.     

基于状态空间模型的机床加工精度分析

伺服进给系统的机电耦合特性直接影响数控机床的加工精度，单独针对伺服系统或机械系统建立的模型不足以准确分析系统参数对机床整机加工精度的影响。因此，综合考虑机床伺服系统与机械结构之间的耦合关系，建立伺服进给系统机电耦合动力学模型具有重要意义。首先，为保证伺服进给系统建模精度，利用状态空间法建立了机床机电耦合状态空间方程。其次，建立了伺服进给系统机电耦合Simulink模型，在此基础上采用复合控制提高系统的响应速度和加工精度。随后，利用多体动力学软件建立机床进给系统的刚柔耦合动力学模型，添加摩擦、阻尼等非线性因素，并导入Simulink与伺服系统建立耦合关系。最终，建立了卧式加工中心伺服进给系统的刚柔-机电耦合仿真加工平台，通过模拟机床加工轨迹以验证机电耦合状态空间模型的可靠性。结果表明：该状态空间模型能准确描述系统内部参数和系统输入输出的耦合关系；采用复合控制结构能有效提高系统的响应速度和加工精度。研究结果为数控机床的仿真建模和提高加工精度提供理论依据，为机床机电系统的设计提供有效指导。     

CAD/CAPP/CAM集成系统的研究与开发

文章介绍了可实用的CAD/CAPP/CAM集成系统。该系统是由机械产品设计人员,工艺人员和数控机床NC编程人员共同努力,在商品CAD/CAM软件Pro/ENGINEER平台上开发的。系统由三个子系统组成：零件信息识别子系统,CAPP子系统和自动CAM子系统。零件信息识别子系统从三维零件中提取零件信息,CAPP子系统分析零件信息,自动生成零件加工工序和工步,从刀具数据库中查询刀具及切削用量,并完成各工序的工步排序。自动CAM子系统根据CAPP的结果,自动生成Pro/ENGINEER的NC工步,经过NC仿真后     

Tool management in flexible manufacturing systems with network part program

Recent technological developments have allowed a new concept of a part program to execute the machining operations that remove the software constraints introduced by the numerical control of machining centres. This change allows machines executing a part program to be structured as a net of operations and not linearly as normally happens in shop floors. The main advantage of using the network part program in numerically controlled machines is that it gives the system more flexibility by increasing the number of alternatives that machines can follow during work. In such a way, machines select their path in the network part program taking into account the dynamic state of resources (e.g. spindles, tools, carriers, pallets, etc.). The paper contains a study on the flexibility related to network part program exploitation in numerically controlled machines. Easy-to-calculate indicators are also defined. They estimate the potential flexibility of a network part program related to a particular product. The study has allowed the definition of a new tool management rule to be used in a flexible manufacturing system where the tools are shared dynamically among machines. The numerical results carried out on two different real cases demonstrate the validity of the new concept by quantifying the advantages in terms of throughput increment and machine idle-time reduction.